as soon as fish are ready to eat. all of my fish have eaten that night, but that is unusual. when you say stocked..... are you talking about one fish? i hope you didnt buy a bunch of fish for your tank right off the bat.
I feed my fish as soon as they are acclimated to the tank.and yes please dont add a ton of fish to your tank all at once the bioload spike will skyrocket and stress your fish beyond beleif one or two fish at a time causes enough increase as it is.I also dose my tanks with melafix when adding new tank mates for 3 days this reduces the stress on all of your stock which in turn reduces the risk of ich